Hair straightener



FIG. 1 is a front elevational view of a hair straightener showing my new design;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a left side view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof;

FIG. 7 is a top, front and right side perspective view thereof;

FIG. 8 is a bottom, rear and right side perspective view thereof; and,

FIG. 9 is a top, front and right side perspective view showing the hair straightener in an open state.

The broken lines in the drawings illustrate portions of the hair straightener which form no part of the claimed design. 

CLAIM The ornamental design for a hair straightener, as shown and described. 